Sylvania



H. F. BETHUNE.

RHEOSTAT.

APPLICATION FILED MAR. 1, 1911.

Patented Aug. 8, 1916.

2 SHEETS-SHEET I.

i nhn WiTNESSES'. 65.1

INVE TOR :ATTORNEY H. F. BETHUNE.

RHEOSTAT.

APPLICATION FILED MAR-1.1911.

2 SHEETS- SHEET 2.

Patented Aug. 8, 1916.

INVENTOR ATTURNEY J WITNESSES:

UNITED s'rarns grnntr OFFICE.

HARRY F. BETHU'NE, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

RHEOSTAT.

To all whom at may concern Be it known that I, HARRY F. BETHUNE, acitizen of the United States, and a resident of Vilkinsburg, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Rheostats, of which the following is aspecification.

My invention relates to electrically operated remotecontrol rheostatsand it has special reference to such devices as are adapted 'to beoperated by electro-magnets.

The object of my invention is to provide a comparatively inexpensivedevice, of the above indicated class, which shall be exceptionallyeffective and reliable in operation.

Heretofore, it has been common to employ remote-control rheostats forregulating the speed of motor-driven machinery or the voltage ofgenerating units. In general, however, such devices have beenmotordriven and have, therefore, involved considerable unnecessaryexpense. Electromagnetically operated field rheostats have also beenemployed to some extent, but have not proved entirely satisfactory, froman operating standpoint, on account of their non-uniform intermittentaction and non-adjustable speed of operation.

According to my invention, I provide a rheostat that may be operated ata predetermined uniform speed, in either direction, by independentelectro-m'agnets, and embodies means for regulating the speed ofoperation, means for automatically arresting the operation at the limitsof travel in either direction, and means for effecting a positiveanduniform operation in either direction, of rotation.

In the accompanying drawings, Figure 1 is a back view of a rheostatconstructed in accordance with my invention, a portion of' Specificationof Letters Patent.

Patented Aug. 8, 1916.

Application filed March 1, 1911. Serial No. 611,730.

panel 8'and supports the various parts of the operating mechanism, whilethe resistor 9 may be arranged and mounted 'on the back of the panel 8in the usual manner. The resistor 9 may be constructed in any well knownmanner and is sub-divided into a plurality of units 21, each of which isconnected "between adacent contact buttons 10 which are disposed uponthe face of the insulating panel 8 in the form of a circle. Therotatable arm 11 is rigidly fastened to the ratchet wheel 12, which ismounted upon a shaft 22 having an insulating handle 23 secured at itsouter end. The proportions of theratchet wheel and the number of notchesthereon are so chosen that the contact arm 11 is advanced from center tocenter of the contact buttons as the device is operated.

The electro-magnets 13 and 14, which are suitably mounted upon thesupporting frame 7, are of like construction and each comprises ,astationary core 24, a movable core 25, and a magnet winding 26. Theoperating levers 15 and 16, which are also of like construction, arepivotally mounted, at their outer ends, upon shafts 27 and 28,respectively, and are pivotally connected, at their inner ends, to thedash pots 18 and 17, re spectively. The levers 15 and 16 are alsopivotally connected to the movable core members of the electroma'gnets13 and 14 recess near the middle of each operating lever, a spring 34being suitable secured to the operating lever to cooperate with the loer end of said dog in order to maintain it in its operating position andto permit it to free itself from the ratchet wheel on the back stroke ofthe operating lever. A projection 35 of the operating lever 15 isdisposed upon the rear side of the ratchet wheel 12 and is adapted to beengaged, under predetermined conditions, by a stop or pin 40, with whichthe'ratchet wheel is provided, for the purpose of limiting the operationin a clockwise direction. Similarly, a projection 35 of the operatinglever 16 is disposed upon the front side of the ratchet wheel 12 andcotiperates with a stop 41 for a similar purpose. A coil spring 36 isadjustably secured between each operating lever, and a boss 37 on thesupporting frame 7.

The dash pots .17 and 18, which are pivotally suspended from pins 42 and43, are of well known construction and perform well known functions.

The make and break devices 19 and 20 are of like construction and eachcomprises a lever member 50 which is pivotally mounted upon a pin 51,near its outer end and is provided, at its inner end, with a projectingportion 52 having buffers 53, of relatively soft material, on itsrespective sides. A coil spring 54 is adjustably secured between theboss 37 and an extension member 55 of the lever 50 and a projection 56of said lever limits its upward movement. Near the inner end of eachlever 50, a supporting member 57 is pivotally'suspended from a pin 58and said member is provided with a contact terminal 59 at each end, saidterminals being electrically connected together and adapted to engagecotjperating stationary contact terminals' 60, under predeterminedconditions. The stationary terminals 60 are secured to a supportingmember 61 which is suitably mounted upon the supporting frame 7. A bodyof magnetizable material 65 is provided upon the lever member 50 toserve as an armature for an electro-magnet. 66 which comprises amagnetizable core member 67, having upwardly projecting end portions 68and a magnet winding 69. The electromagnet 66 is adapted to restrain thelever member 50 until it is released by reason of engagement with one ofthe levers15 and 16.

Assuming the various parts of the device to occupy the positions shownin the drawings, it will be observed that all of the resistor 9 is outout of the field circuit of anotor 3"and the contact arm 11 is in itsextreme counter-clockwise position. The motor 3 ,is adjusted, therefore,for slow speed operation. If it should be desired to increase the speedof motor 3, a double-throw switch 70is closed upon a stationar tactterminal 71, thereby completing a circuit from the line conductor,through conductor 72, switch member 70, stationary contact terminal 71,conductor 7 3, stationary contact terminals 60, movable contactterminals 59, conductor 74, magnet winding 69, conductor 75, the winding26 of the magnet 13 and conductor 76 to the line conductor 2. Upon thecompletion of the circuit just recitedfthe electro-magnet 66 of the makeand break device 20 and the operating electromagnet 13 become energizedand the operating lever 15 is raised, thereby causing the dog 32 toengage oneof the notches of the ratchet Wheel 12 and to actuate it in aclockwise direction.

Inasmuch as the tension of coil spring 54 is less than the force exertedby the electromagnet 66, the coiiperating contact terminals 59 and 60are maintained in engagement as long as electro-magnet 66 is energized.As the operating lever 15 reaches the top of its stroke, however, theadjustable setscrew 30 engages the bottom cushion 53 of .the projectingportions of the lever 50 action of the dash pot 18 which introduces apredetermined time element. It will be understood that, by varying thetension of the spring 36, the speed of operation may also be varied, asdesired. As the lever member 15 falls to its lowest position, the loweredge of the web 31 engages the upper cushion 53 of the projectingportion 52 of the lever member 50 and thus causes engagement of thestationary and movable contact terminals 59 and 60. It is evident,therefore, that the energizing circuit is again established and that thecycle of operation just recited will be continued intermittently untilthe switch member 70 is disengaged from its contact terminal 71, as willbe readily understood.

Those skilled in the art will readily understand that, as the ratchetwheel 12 and contact arm 11 are rotated, step-by-step, in a clockwisedirection, the resistor 9 is cut into the field circuit of the motor 3and, hence, its speed is increased, according to Well known principles.Assuming the contact arm 11 to occupy some intermediate position withrespect to the resistor 9, it is evident that a decrease in motor speedmay be effected, in a similar manner, by closing switclnmember 70 upon acontact terminal 80, whereby a circuit through the make and break device19 and the operating electromagnet 14 is established.

On account of the simplicity of the circuit arrangements and thesimilarity to those hereinbefore described, it is believed that thoseskilled in the art will experience no difiiculty in understanding thecircuit connections and the mode of operation in a counter-clockwisedirection.

Assuming that the switch member 70 closed upon the contact terminal 80,thereby causing movement of the contact arm in a counterclockwisedirection, it is evident that intermittent rotation continuesautomatically until the contact arm 11 has reached its limit of travelin a counter-clockwise direction, in which position the stop ll isadvanced to make contact with the projecting member of the operatinglever 16 and thus prevents the closure of the cooperating contactterminals 59 and 60 of the make and break'device 19. Hence, theoperation of the rheostat is automatically discontinued and theenergizing circuits are interrupted. In a similar manner, the operationin a reverse direction is automatically arrested at the limit of travel.

It is evident that a definite and positive operation of the apparatus iseffected by reason of the direct means of actuating the make and breakdevices 19 and 20 and the cooperative action of the electro-magnets 66,as hereinbefore described, and hence a uniform speed of operation issecured.

My invention is not restricted to use with rheostats alone, as variousclasses dfiapparatus, in which arot'ative movement is required, may alsobe operated by similar means and in a similar manner. Neither is thedevice in question limited to'operation in two directions, as certaintypes of apparatus to which my invention pertains, are essentiallyadapted for uni-directional rotation.

While I have illustrated and described a circuit controlling device of aspecific structure and circuit arrangements, it is evident that manymodifications may be effected in the size, arrangement and location ofparts and circuit connections, without exceeding the scope and spirit ofmy invention. and I desire that only such limitations shall be.imposedas are indicated in the appended claims.

.I claim as my invention:

1. The combination with a rheostat comprising cooperating stationary andmovable contact members and a resistor connected to .said stationarycontact members, of a ratchet wheel, rigidly associated with saidmovable member, lndependent operating mechanisms for intermittentlyactuating said ratchet wheel, each comprising an electro-magnet, a

pawl, a time element device, a positively actuated make and break deviceand an electromagnet connected in series circuit with said make andbreak devicefor effecting the operation thereof.

2. The combination with a rheostat comprising cooperating stationary andmovable contact members, and a resistor connected to said stationarycontact members, of a ratchet wheel rigidly associated with said movablemember, independent and duplicate means for actuating said ratchet wheelin opposite directions, each comprising an electro-magnet, a pi'votallymounted pawl member connected to said electro-magnet, a time elementdevice associated with said pawl member, means positively actuated bysaid pawl member for intermittently app ying elec trical energy to saidelectro-magnet and means in circuit with said electro-magnet foropposing said last means.

3. In a rheostat, the combination with a plurality of resistanceelements, a set of stationary contact terminals disposed in a circle andconnectedvthereto, and a movable contact arm to cooperate with saidcontact ter minals, of a ratchet member rigidly associated with Saidmovable arm, independent and duplicate operating mechanisms em bodyingelectro-magnets adapted to cause movement of said ratchet member inopposite directions, make and break devices associated with eachoperating mechanism and normally arranged to close the energizingcircuits of the respective electro-magnets,

electro-magnetic means tending to maintain said devices closed and meansassociated with said operating mechanism for positively opening andpositively closing said make and break devices subsequent to theoperative movement of said mechanism.

4. In a rheostat, the combination with cooperating stationary andmovable contact members, and resistance elements associated therewith,of a ratchet wheel associated with the movable member, independentoperating mechanisms embodying electro-magnets for actuating said wheelin opposite directions, and make and break devices electricallyassociated with said electro-magnets and embodying cooperating movableand stationary contact terminals, and electro-magnets normally arrangedin series circuit with said operating electro-magnet's and saidcooperating contact terminals and adapted to maintain engagement of saidcooperating terminals, said operating mechanisms being adapted to effectthe initial separation of said contact terminals subsequent to themovement of said ratchet wheel.

5. The combination with a rotatable member, a ratchet wheel attachedthereto and independent electricallv operated means for intermittentlyactuating said wheel in either direction, of adjustable means forregulating ,the speed of operation in either direction, means forsecurmg a uniform speed of oper- 7 The combination with a rotatablemember and means for intermittently actuatingsaid member, of means forregulating the speed of operation thereof, and means in'-' eluding anintermittently energized coil and actuated solely by said first meansfor maintaining a uniform step by step rotative movement.

8. In a rheostat, the "combination with a plurality of stationarycontact terminals, a plurality of resistance elements connected theretoand a movable arm to cooperate with said contact terminals, of anadjustable electrically operated means for intermittently actuating saidcontact arm and intermittently energized electromagnetic means and apositively actuated circuit controlling means for governing theoperation of said electrically operated means.

- 9. The combination with a rotatable member and an operating mechanismtherefor embodying a working electro-magnet, of a make-and-break deviceembodying cooperating contact terminals and an auxiliary electromagnetboth normally connected in series withsaid working elec'tromagnet.

10. The combination with a rotatable member and an operating mechanismtherevior embodying a working electro-magnet, of.

a make-and-break device embodying cooperating contact terminals inseries circuit with said working electro-magnet and electromagneticmeans included in the same circuit tending to maintain said contactterminals in engagement.

In testimony whereot, I have hereunto subscribed my name this 18th dayof February,

HARRY F. BETHUNE. -Witnesse s: v

H. G. YoUNGBLooo, KANUTH BUCHANAN.

